Polarizing beamsplitter (PBS) cubes

Polarizing Beamsplitter (PBS) cubes are used to split a randomly polarized beam into two orthogonal, linearly polarized components. S-polarized light is reflected at a 90° angle, while P-polarized light is transmitted through the cube. Each cube consists of two right-angle prisms with a dielectric polarizing beamsplitter coating applied to the hypotenuse of one prism. The incident light should strike the coated prism first to minimize energy passing through the optical glue. If the light enters from the opposite side, the optical glue will experience significantly more energy, leading to degradation over time. To reduce light loss, AR coatings are commonly applied to the entrance and exit faces of the cube.

3photon offers two types of PBS cubes based on prism assembly:

Standard PBS Cubes: Glued cubes designed for low- and medium-power applications

The interface is cemented with optical glue, limiting their use to applications with laser damage thresholds >0.3 J/cm² @ 1064 nm. These cubes can achieve Tp > 95% @ 1064 nm and an extinction ratio of up to >500:1.

High-Power PBS Cubes: Optically bonded cubes designed for high-power lasers.

The interface prisms are bonded using advanced optical contact technology, allowing for a much higher laser damage threshold (>15 J/cm² @ 1064 nm). These cubes achieve Tp > 97% @ 1064 nm (Tp > 96% @ 355 nm) and an extinction ratio of up to >1000:1. High-precision elements are used in their construction.